Description: (Applicant's Description) Exploration of the human papillomavirus (HPV) capsid represents a novel strategy for the delivery of DNA vaccines to desired cells. HPV capsid proteins can be used to contain DNA vaccines, forming pseudovirions that protect DNA from nuclease activity and improve vaccine stability. Furthermore, HPV pseudovirions may also enhance delivery of a therapeutic DNA vaccine to dendritic cells since they express a6 integrin which can bind dendritic cell receptors. We have previously developed two DNA vaccine strategies that enhanced class I and/or class II presentation and can be incorporated into pseudovirions. One of these strategies is the linkage of the lysosome associated membrane protein (LAMP-1) sorting signal to a model antigen. We demonstrated that expression of this chimeric protein targeted model antigen to the endosomal and lysosomal compartments, thereby enhancing MHC class II presentation of the model antigen to CD4+ T cells. Additionally, we developed a vaccine strategy by linking a model antigen to Mycobacterium tuberculosis heat chock protein 70 (HSP70). We demonstrated that vaccination with this DNA construct enhanced MHC class I presentation of the model antigen to CD8+T cells. One of the major goals in the current proposal is to determine whether the combination of these vaccine strategies in the context of pseudovirions is able to generate enhanced CD4+ and CD8+ T cell responses and potent anti-tumor immunity specifically against HER-2/neu, the model antigen expressed in breast cancer tumors. Specifically, we plan to 1) generate and characterize the expression of HPV-16 (sig/HER-s/neu/LAMP-1) and HPV-16 (HER-2/neu/HSP70) pseudovirions in vitro and in vivo. 2) Compare the ability of HPV-16 (Sig/HER-2/neu/LAMP-1) and HPV-16 (HER-2/neu/HSP70) pseudovirions to induce HER-2/neu-specific humoral and cell-mediated immune responses with each other and with corresponding naked DNA vaccines. 3) Compare the anti-tumor effects generated by HPV-16 (Sig/HER-2/neu/LAMP-1) and HPV-16 (HER-2/neu/HSP70) pseudovirions with each other and with corresponding naked DNA vaccines using HER-2/neu-expressing murine tumor models. 4) Evaluate potential synergistic applications of HPV-16 (Sig/HER-2/neu/LAMP-1) and HPV-16 (HER-2/neu/HSP70) pseudovirion vaccines for enhancement of anti-tumor immunity. 5) Evaluate the mechanisms of anti-tumor immunity in the optimal vaccine approach.